Question

Solve x2 - 8x - 9 = 0. Rewrite the equation so that it is of the form x2 + bx = c.

Answer 1

X^2 - 8x-9=0
D = b^2- 4*a*c = 64- 4* (-9) = 64+36=100 =10^2
X1 = (8-10)/2 = -1
X2= (8+10)/2= 9